Contours are not projected, but are provided in geographic coordinates (latitude and longitude) in units of decimal degrees, and horizontally referenced to the North American Datum of 1983. Contour elevation values are vertically referenced to the North American Vertical Datum of 1988. Contours are staged in Esri File Geodatabase 10.1 or Shapefile format, and distributed in 1x1 degree tiles.
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Are depression contours identified in 3D Elevation Program (3DEP) contour products?
Yes, depression contours are identified with tick marks in 3D Elevation Program products, but only in large scale contours (1:36,000 scale to 1:18,000 scale).
What geographic areas do 3D Elevation Program (3DEP) contours cover?
3D Elevation Program (3DEP) contours cover all of the United States and its territories at multiple scales: Small scales (1:578,000-1:289,000) Medium scales (1:144,000-1:72,000) Large scales (1:36,000-1:18,000) Contours are easily viewed in The National Map Viewer and USGS topographic maps, or downloaded through The National Map Download Client. Learn more: Map Scales
What is the difference between lidar data and a digital elevation model (DEM)?
Light detection and ranging (lidar) data are collected from aircraft using sensors that detect the reflections of a pulsed laser beam. The reflections are recorded as millions of individual points, collectively called a “point cloud,” that represent the 3D positions of objects on the surface including buildings, vegetation, and the ground. Digital elevation models (DEMs) are one of many products...
Are 3D Elevation Program (3DEP) contour lines updated and what sources were used to create them?
When significant changes in the landscape have occurred, contours will be updated on an as-needed basis. The 100-foot contours were derived from 3DEP (formerly National Elevation Dataset) one arc-second resolution data that was sub-sampled to a cell size of three arc-second. The 50-foot contours were also derived from one arc-second data. Large-scale contours were derived from 1/3 arc-second...
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- FAQ
Are depression contours identified in 3D Elevation Program (3DEP) contour products?
Yes, depression contours are identified with tick marks in 3D Elevation Program products, but only in large scale contours (1:36,000 scale to 1:18,000 scale).
What geographic areas do 3D Elevation Program (3DEP) contours cover?
3D Elevation Program (3DEP) contours cover all of the United States and its territories at multiple scales: Small scales (1:578,000-1:289,000) Medium scales (1:144,000-1:72,000) Large scales (1:36,000-1:18,000) Contours are easily viewed in The National Map Viewer and USGS topographic maps, or downloaded through The National Map Download Client. Learn more: Map Scales
What is the difference between lidar data and a digital elevation model (DEM)?
Light detection and ranging (lidar) data are collected from aircraft using sensors that detect the reflections of a pulsed laser beam. The reflections are recorded as millions of individual points, collectively called a “point cloud,” that represent the 3D positions of objects on the surface including buildings, vegetation, and the ground. Digital elevation models (DEMs) are one of many products...
Are 3D Elevation Program (3DEP) contour lines updated and what sources were used to create them?
When significant changes in the landscape have occurred, contours will be updated on an as-needed basis. The 100-foot contours were derived from 3DEP (formerly National Elevation Dataset) one arc-second resolution data that was sub-sampled to a cell size of three arc-second. The 50-foot contours were also derived from one arc-second data. Large-scale contours were derived from 1/3 arc-second...
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